Hanayama Cast Puzzle: Vortex (Level 6)

Three near-identical metal spirals coiled into each other, each with protrusions stopping the whole thing coming apart. Akio Yamamoto's hint is simply: think 'crest'.

Rated Level 6 of 6 on Hanayama's difficulty scale — the top of the scale, and not a bluff.

Hanayama's Huzzle Cast series is the benchmark for mechanical puzzles — solid cast metal, no instructions in the box, and a single instruction: take it apart, then put it back together. The reassembly is always the harder half.

Pocket-sized, satisfyingly heavy, and it will be picked up by everyone who walks past your desk. Solutions are available from Hanayama if you need them, though most people hold out longer than they expect to.

Perfect for: desk fidgeters, puzzle collectors, Secret Santa, and anyone who claims to be good at this sort of thing.